1. Field of the Disclosure
Apparatuses and methods consistent with exemplary embodiments of the present disclosure relate to a backlight unit and a display apparatus having the same, and more particularly, to a backlight unit that irradiates the light of two types of light sources onto a light guide plate, and a display apparatus having the same.
2. Description of Related Art
A display apparatus is an apparatus operable to display an image by using a display panel. Display apparatuses are used in various types of devices, such as televisions (TVs), computer monitors, smartphones, tablets, etc.
However, some existing display apparatuses do not autonomously emit light and thus require an additional light source, such as a backlight unit. In some display apparatuses, the backlight unit is disposed behind the display panel. The backlight unit may be an edge-lit type unit, which requires a light guide plate uniformly guiding light irradiated from a light source to the display panel, or a direct-lit type unit, which does not require a light guide plate. In the direct-lit type backlight unit, a light source is disposed directly behind the display panel. This may result in an increased thickness of the display apparatus. However, some users demand thinner display apparatuses. In the edge-lit type backlight unit, a light source is disposed on a side of a light guide plate. This configuration allows display apparatuses using an edge-lit type backlight unit to be thinner than display apparatuses using a direct-lit type backlight unit.
Light-emitting diodes (LEDs) have been used as a light source in backlight units. LEDs have the advantages of a long lifespan, low power consumption, etc.
Backlight units that use LEDs as a light source may use white light, which is formed by a mixture of red, green, and blue light emitted from LEDs, as a backlight of a display apparatus. However, red, green, and blue light emitted from LEDs have different widths and strengths of wavelengths, and thus uniformities of the red, green, and blue lights may be impaired. As a result, when using LEDs as backlight, it may be difficult to realize white light similar to natural light, and thus a color reproduction range of the LED backlight unit may be impaired.
As a result of demands for display apparatuses that realize ultra-high definition (UHD) screens, two types of light source backlight units may be used along with a laser diode (LD) in an LED light source to improve a color reproduction range of a backlight unit using only an LED as a light source. However, if two types of light sources are used in a backlight unit, the emission distribution of light emitted from the two types of light sources may be different. Further, light guide plates may be necessary for the two types of light sources. As a result, an overall thickness of the backlight unit using the two types of light sources may become thicker due to an increase in the number of light guide plates.